1. Field of the Invention
The present invention is directed to a ski binding for securing a ski shoe or boot to a ski, and more particularly to a safety binding used in cross-country skiing.
2. Description of Prior Art
Numerous bindings are known for use in cross-country skiing which are adapted to maintain the front end of the shoe or boot secured to the ski while allowing the heel of the shoe to be raised.
French Pat. No. 2,304,368 illustrates a binding in which the front portion of the boot is rigidly and definitely secured during skiing, with the only possible movement of the shoe being the lifting of the heel to allow for walking. To assure a good guidance of the ski during walking (with the ski), the maintenance of the front of the sole must be sufficiently rigid to avoid torsion of the foot around a vertical axis. The greater the lateral rigidity and security, the more accurate is the direction of the skis. However, this advantage is not also without disadvantage. In effect, under these conditions, there is increased danger to the leg of the skier, which can end up in positions where the lateral movement of the foot or its release is necessary to avoid fracture.
Certain manufacturers provide a safety binding for use in cross-country skiing which releases the shoe, as is currently done, and as was long the case in Alpine-type ski bindings. German application Nos. 29 07 359 and 29 07 365 can be cited as examples of such embodiments.
In the above German patents, it is noted that the front of the sole is releasably secured to the ski. The sole is either fixed in a stirrup, or in a jaw which is releasable with respect to the ski. In each of these embodiments, the torsion of the foot along an axis parallel, or not, to the tibia is possible against the force of an elastic energization system. Furthermore, when the torsion reaches a sufficient value, release of the foot of the skier from the ski occurs in the same manner as in Alpine-type bindings.
This type of arrangement is of definite interest with respect to safety, but suffers from undeniable disadvantages with respect to skiability. In effect, the front of the foot is linked to the ski in an elastic fashion. There is thus a poor holding of the shoe, and the elastic maintenance of the shoe does not allow for a very precise steering and direction of the skis.